Pet doors available on the market today generally consist of soft plastic or aluminum materials which hang by gravity, typically from a swingably mounted utility door, and are sealed by magnetic means. Other doors have an overlapping of plastic material in such a way as to prevent excessive weather penetration. Both of these pet door devices operate by means of the pet having to push against the door or flap with its head in order to enter or exit.
A significant disadvantage of these pet doors of the prior art is that some pets (especially small pets) simply will not push against the door for one reason or another. Most other pet doors are installed in the rear swinging door of the garage. Another disadvantage is the inconvenience of having a flap door mechanism extending from a utility door with the possibility of snagging or catching the operator. Another disadvantage is that swinging doors of the prior art take up valuable wall space when they are opened, in addition to posing the hazards of snagging or injuring those nearby.
A further disadvantage is that the magnetic flaps or plastic materials used for weatherproofing many prior art pet doors do not match to the intended correct closed position. For this reason, installation of these conventional pet doors in the main living quarters of the house is not practical. Moreover, conventional pet doors of the prior art also permit access to potential thieves and other animals and rodents.
Many of the above disadvantages have been overcome in the automatic pet door disclosed in the U.S. Pat. No. 5,177,900 to Solowiej. The U.S. Pat. No. 5,177,900 discloses an automatic pet door apparatus with a door vertically slidable within the frame between closed and open positions by way of a driver in response to a signal. A pet wears a radiation transmitter that produces the signal activating a transducer, causing the driver to be energized and raise the door. However, the automatic pet door apparatus disclosed in the U.S. Pat. No. 5,177,900 has disadvantages in that the driver disclosed therein is unreliable and does not provide efficient way to prevent unauthorized opening of the door, and also, the radiation transmitter requires a battery to operate, which makes it unreliable (due to battery discharge, exposure to water and shock), as well as bulky to wear for small pets.
Thus, there is a need for a pet door that overcomes the above disadvantages, being operated without the pet having to force it open, yet being secure against thieves and is reliably weatherproof, and is inexpensive to provide and install.